Electrical unit mounting assembly



March 24, 1959 G. J. MUCHER 2,879,363

ELECTRICAL UNIT MOUNTING ASSEMBLY Filed June 28, 1954' 2 sheets-sheet 1.

I (20 m ]K II/III Il/ IgI/III VIII/III] INVENTOR [Magg e f Marker 1 2% ATTORNEYS March 24, 1959 GQJ. MUCHER ELECTRICAL UNIT MOUNTING ASSEMBLY 2 Sheets-Sheet 2 Filed June 28, 1954 iNvENfoR (720;?! Marker M ATTQ RN EYS United States Patent 6 ELECTRICAL UNIT MOUNTING ASSEMBLY GeorgeJ. Mucher, Rochester, N.H., assignor to Clarostat lg lfg. Co., Inc., Dover, N.H., a corporation of New ork Application June 28, 1954, Serial No. 439,608

3 Claims. (Cl. 201-67) This invention relates to a structurally and functionally improved mounting and unit; the unit being of the electrical type and in its more specific and preferred embodiments embracing a resistor.

By means of the present invention an assembly is furnished which will be of extremely desirable type and which may readily be plugged in orif necessary-removed from association with an electrical circuit, that circuit being conveniently of the printed type.

A further object is that of providing an improved terminal structure forming a part of a resistor and which latter, together with its terminals, may readily be manufactured by quantity production methods so that an economically priced unit will be produced which will have a long effective life.

With these and otherobjects in mind, reference is had to theattached sheets of drawings illustrating practical embodiments of the invention and in which:

Fig. l is a sectional side view of a resistor unit in partially completed condition;

Fig. 2 is a longitudinal sectional front view taken along the line 22 in the direction of the arrows as indicated in Fig. 1;

Figs. 3, 4, and 6 are transverse sectional views taken respectively along the lines 33, 4-4, 5--5 and 65 and in the direction of the arrows as also indicated in Fig. 1;

Fig. 7 is a perspective view of the resistor element with the terminals attached thereto;

Fig. 8 is a similar view of a further terminal and lead for connection to the resistor;

Fig. 9 is a view similar toFig. 2 but showing the resister in completed condition;

Fig. 10 is a view similar to Fig. 2 but illustrating an alternative form of terminal structure;

Fig. 11 is a transverse sectional view taken along the line '1111'in the direction of the arrows as indicated in Fig. 10;

Fig. 12 illustrates portionsof the resistor and its terminal orconnecting element prior to assembly with each other'as in Fig. 10, and

Fig. 13 is an enlarged perspective view of these elements and showing them combined with each other.

Referenceis primarily had to the United States patent to'Geroge'J. Mucher, No. 2,538,977, dated January 23, 1951. In that patent there is shown and described a resistor which, as especiallyillustrated in Figs. 5 to 11, inclusive, involves alunit bent upon itself to embrace a generally U-shaped configuration. That unit is disposed within a tube of suitable material and has connected to its ends terminals which project beyond the adjacent tube end and by means of which the device may be coupled to form part of an electrical circuit. The parts disposed within the tube are retained against displacement by having the inner tube face formed with one or more recesses. 'Parts of the terminals extend into these recesses and are thus braced against undesired movements. The

2,879,363 Fate-rated Mar. 24, 1959 unit being thereupon preferably filled with a mass of material having high insulating and heat conducting characteristics, it follows that the parts are properly anchored so that the tube, the elements contained therein and the terminals extending therefrom are, in elfect, a single rigid assembly.

Under certain techniques now prevailing, so-called printed circuits are employed. Those circuits involve a base of insulating material upon which is diagrammed, by a conducting material, the various leads, branches, main lines, etc., which provide the complete desired circuit. At proper positions the base is formed with openings. These receive the terminals secured to the various electrical controls such as otentiometers, resistors, etc. Considerable force has to be exerted in plugging-in the terminals so that they extend through the openings and adjacent or within the area of printed circuit portions. Thereafter, by suitable soldering or other technique, the terminals are more or less permanently combined with the panel. In the case of variable resistances, potentiometers and similar units, little difficulty is experienced in properly connecting suitable terminals embodying plugin characteristics with these units. Terminals thus provided will readily withstand the substantial strains which are exerted on the units as they are mounted upon or removed from the panel carrying the printed circuit.

However, in the case of resistors, it has heretofore been necessary to employ the more or less conventional type of terminal. That terminal has not been desirable for use with printed circuits such as afore described. More particularly, it has tended to deflect or distort .as it has been forced through the openings or slots in the base to either associate it with that base or remove it therefrom. However, by employing a resistor shell or tube of the type shown in the afore identified Mucher patent and suitably modifying the terminal extending therefrom, a structure is provided which will permit of a ready coupling with or detachment from the panel. That structure will initially assume a proper disposition with reference to the panel layout as the operator aligns the terminals and axially projects the unit towards the panel. With the completion of mounting electrical connection is established with the circuit. Thereafter these terminals may readily receive solder in accordance with conventional techniqueso that the resistor becomes, in effect, an integral part of the assembly.

Thus, referring to Figs. 1 to 9, inclusive, the numeral 15 indicates the tube or casing of the unit which may be formed of a suitable ceramic. One end of that tube is closed, as at 16, the opposite end being open. A resistor may conveniently include sections 17 each embracing a wire wound core. These sections are connected adjacent their upper ends by a bridging strip 18. The latter is, for example, clamped around a convoluted area of the upper part of each section 17. A lead 19 may extend downwardly from the element 18 as inFig. 8.

As shown especially in Figs. 3, 4 and 5 inwardly extending ribs or flutes 20 may be provided as integral parts of tube 15. Between them they will, in effect, furnish compartments, two of which receive the sections 17 and one of which receives the lead 19. As will be observed, referring to those figures, these compartments continue throughout the length of the tube to a point at least adjacent its lower or inner end.

As taught in the prior Mucher patent, terminals are coupled one to each of the lower or inner ends of the resistor. These terminals are preferably of sheet metal and as illustrated especially in Fig. 7, include clamping or bracing portions 21 which are constricted around the lower ends of sections 17 to be in electrical connection 4 therewith. Beyond these they may each be angularly offset as indicated at 22 and thence extend axially of the section 17 to furnish a bracing portion 23. The latter, as illustrated in Figs. 4 and 5, extends across the compartment or recess defined between an adjacent pairof the ribs 20. It engages the surfaces of the latter and is thus locked against movement with respect to the tube. At a point beyond this bracing portion the terminals connected to sections 17 are each extended outwardly as at 24 and thence downwardly or again in an axial direction.

With the parts properly disposed, the outwardly extending portions 24 lie adjacent and in engagement with the lower edge of tube 15. In this manner the terminals are further supported and braced. They should be formed of a metal having resilient characteristics. Conveniently they will embody in their final axially extending parts detent portions 25 which terminate in guiding ends 26. The width of the latter and the detent portions is such that they may pass through openings 28 formed in amounting panel 29. The latter carries preferably printed circuits in accordance with accepted technique. Too great a penetration of the terminals through the openings 28 is prevented by conveniently having the terminal strips provided with enlarged parts 30 intervening the arms in which the detents 25 are included and the outwardly extending surfaces 24. In this manner stops are furnished which engage against the surface of the panel at points adjacent the openings to arrest inward movement of the resistor assemblies with respect to the panel.

Of course, as has been taught in the aforeidentified Mucher patent, the interior of the tube 15 is filled with a mass 31 of material embodying insulating characteristics as well as high heat conductivity. Such a mass will completely secure all parts of the assembly against detachment or movements with respect to the tube within which they are contained. Also, it will assure a firm bracing of the parts.

As shown especially in Fig. 8, the terminal connected to lead 19 may be identical with the terminals connected to sections 17 excepting only that it does not include a clamping portion 21. Rather, it begins with an axially extending part 32 corresponding to part 23 and below which it is continued in an outwardly or laterally projecting portion 33 to underlie the edge of tube 15 and also includes a stop part 34, a detent portion 35 and a guiding end 36. Any suitable form of coupling such as spot welding may exist between lead 19 and the terminal as illustrated in Fig. 8.

In any event, it will be appreciated that the construction thus furnished follows functionally the teachings of the aforeidentified Mucher patent. Accordingly, the terminals are braced against both axial and lateral movements. Therefore, the detents 25 will readily pass through the slots of openings in the panel and cam against the'edges of the latter as they reach their fully and properly disposed positions under the considerable thrust which has to be exerted to achieve this result. Despite that thrust, no displacement of the parts will occur because of the aforedescribed anchoring relationship which is embodied in the assembly and the fact that any thrusts in an inward direction are largely absorbed and counteracted as a consequence of the outwardly extending portions 24 in engagement with the edge of tube 15. Strains in an opposite direction have no effect on the unit because the terminals are anchored into the recesses forming parts of the tube and those portions of the terminals which project beyond the body of the resistor have suflicient resiliency to allow of a flexing of the parts.

' Thus, a unit is furnished which does not have to be provided with a locating plug andwhich at the same time will'adhere to the strict tolerances which must necessarily be followed in the spacing of'the terminals so that they conform to the spacing of the circuit parts. Also, when the resistors are in mounted position, the detents 25 will not alone assure a proper retention of the units, but will also provide for a reliable electrical connection between the terminals and the circuit leads.

If it is desired to employ terminals different than those shown in Figs. 1 to 9, inclusive, this may readily be done in accordance with the present teachings and without detriment to the functioning of the resultant product. More particularly, as shown in Figs. 10 and 11 an assembly may include the tube 15 as afore described and which is provided with flutes or ribs 20 in order to furnish the relatively recessed portions. A resistor 37 of U-shape may be disposed within the tube. A lead may of course be connected to the resistor at any desired point intermediate its ends and corresponding in function to lead 19. In any event, the ends of resistor 37 are received within the helical portions 39 of terminal leads 40. After the parts are thus disposed, the convolutions are compressed around the adjacent end portion of the resistor element to establish a proper electrical connection. In such compressinga configuration results which embraces a curvilinear triangle as shown in Figs. 11 and 13; This triangular outline embraces a relatively long side portion 41. That side portion lies within the recesses defined between ribs 20 and in engagement with the adjacent inner face of the tube. Therefore, the parts are adequately braced in the same manner as heretofore described without the necessity of employing complicated and costly dies. Also, more axial space exists within the tube than which was formerly occupied by terminal portions.

Under these circumstances, the outer ends of leadsftfl may be suitably formed to permit of a ready disposition of the resistor within a circuit. However, the end of any intermediate lead may be connected to a terminal and also the ends of leads 40 may likewise be connected to terminals which conform in all general respects with the terminals as heretofore described in the earlier figures.

Thus, among others, the several objects of the invention as specifically aforenoted are achieved. Obviously, numerous changes in construction and rearrangement of the parts might be' resorted to without departing fromthe spirit of the invention as defined by the claims.

I claim:

1. An electrical unit mounting assembly comprising an extruded insulating tubular casing capped at its upper end and open at its lower end, the inner surface of said tubular casing provided with ribs extending axially along the inner length thereof and with inner curved surfaces between adjacent ribs, a current controlling unit lyng between and against adjacent ribs within said casing and resilient metal terminals each clamped at its upper end to a lower end of said current controlling unit whereby the current controlling unit and clamped terminal portion are restrained from axial movement by being confined within said ribs, said terminals each projecting below said clamped upper end in a substantially perpendicular direction to the'axis of said casing towards said inner curved surface between adjacent ribs and bent at said inner curved surface downwardly to form plug-in elements, an insulating mass at the base of said casing bearing against oppositely placed downwardly extending portions of said terminals with said casing receiving said terminals and current controlling unit against axial and radially off-setting movement and thereby effecting a bracing action of said last named portions of said terminals against said mass and said casing within said casing; the opposite terminals being bent outwardly from the bottom edge of said mass in bearing con tact with the bottom edge of said casing to provide an outer bracing portion of said terminals in bearing relation against the lower edge of said casing and downwardly extending plug-in'portions terminating said terminals.

2. An electrical mounting assembly as defined in claim 1 wherein said terminal comprises a substantially flat i strip of metal, the portion of said terminal being confined between adjacent ribs havinga width substantially equal to the distance between said adjacent ribs.

5 3. A mounting assembly as defined in claim 1 wherein the casing is formed of extruded ceramic material and wherein said insulating mass is formed of a material having high heat-conducting characteristics.

References Cited in the file of this patent 5 UNITED STATES PATENTS 6 Chirelstein Jan. 16, 1940 Stearns July 16, 1940 Funk June 30, 1942 Stoffet Jan. 9, 1945 Mucher Jan. 23, 1951 Arisman et a1 Oct. 18, 1955 Budd et a1. Mar. 27, 1956 FOREIGN PATENTS Great Britain Jan. 7, 1936 

